package com.icl.saxon.tree;
import com.icl.saxon.om.NodeInfo;
import com.icl.saxon.om.NamePool;
import com.icl.saxon.output.Outputter;

import javax.xml.transform.TransformerException;
import org.w3c.dom.Node;

/**
  * A node in the XML parse tree representing a Namespace. Note that this is
  * generated only "on demand", when the namespace axis is expanded.<P>
  * @author <A HREF="mailto:mhkay@iclway.co.uk>Michael H. Kay</A> 
  * @version 3 November 1999
  */

final class NamespaceImpl extends NodeImpl {

    private int nsCode;	    // indexes the prefix and uri in the name pool
    private int nameCode;	// identifies the name of this node
    private int index;

    /**
    * Construct a Namespace node 
    * @param element The element owning the namespace node
    * @param nsCode The namespace code 
    * @param index Integer identifying this namespace node among the nodes for its parent
    */

    public NamespaceImpl(ElementImpl element, int nsCode, int index) {
        this.parent = element;
        this.nsCode = nsCode;
        NamePool pool = getNamePool();
        this.nameCode = pool.allocate("", "", pool.getPrefixFromNamespaceCode(nsCode));
        this.index = index;
    }

	/**
	* Get the namecode for this name. Not the same as the namespace code!
	*/
	
	public int getNameCode() {
		return nameCode;
	}

	/**
	* Get the namespace code for this prefix/uri pair. Not the same as the name code!
	*/
	
	public int getNamespaceCode() {
		return nsCode;
	}

    /**
    * Determine whether this is the same node as another node
    * @return true if this Node object and the supplied Node object represent the
    * same node in the tree.
    */

    public boolean isSameNode(NodeInfo other) {
        if (!(other instanceof NamespaceImpl)) return false;
        if (this==other) return true;
        NamespaceImpl otherN = (NamespaceImpl)other;
        return (parent.isSameNode(otherN.parent) && 
        		this.nsCode==otherN.nsCode);
    }

    /**
    * Get the prefix of the namespace that this node relates to
    */

    public String getLocalName() {
        return getNamePool().getPrefixFromNamespaceCode(nsCode);
    }
    
    /**
    * Change the uri of the namespace that this node relates to
    * (used to implement xsl:namespace-alias)
    */

    public void setNamespaceCode(int nsCode) {
		NamePool pool = getNamePool();
        this.nsCode = nsCode;
        this.nameCode = pool.allocate("", "", pool.getPrefixFromNamespaceCode(nsCode));
    }
    
    /**
    * Return the type of node.
    * @return NodeInfo.NAMESPACE
    */

    public final short getNodeType() {
        return NAMESPACE;
    }

    /**
    * Return the string value of the node. 
    * @return the namespace uri
    */

    public String getStringValue() {
        return getNamePool().getURIFromNamespaceCode(nsCode);
    }
    
    /**
    * Get the name of this node, following the DOM rules (which aren't actually defined
    * for Namespace nodes...)
    * @return the namespace prefix
    */

    public String getNodeName() {
        return getLocalName();
    }

    /**
    * Get next sibling - not defined for namespace nodes
    */

    public Node getNextSibling() {
        return null;
    }

    /**
    * Get previous sibling - not defined for namespace nodes
    */

    public Node getPreviousSibling() {
        return null;
    }

    /**
    * Get the previous node in document order (skipping namespace nodes) 
    */

    public NodeImpl getPreviousInDocument() {
        return (NodeImpl)getParent();
    }

    /**
    * Get the next node in document order (skipping namespace nodes)  
    */

    public NodeImpl getNextInDocument(NodeImpl anchor) {
        if (this==anchor) return null;
        return ((NodeImpl)getParent()).getNextInDocument(anchor);
    }
   

    /**
    * Get sequential key. Returns key of owning element with the namespace prefix as a suffix
    */

    public String generateId() {
        return parent.generateId() + "_xmlns_" + getLocalName();
    }
    
    /**
    * Copy this node to a given outputter
    */

    public void copy(Outputter out) throws TransformerException {
		out.copyNamespaceNode(nsCode);    
    }

    /**
    * Get the node sequence number (in document order). Sequence numbers are monotonic but not
    * consecutive. In the current implementation, parent nodes (elements and roots) have a zero
    * least-significant word, while namespaces, attributes, text nodes, comments, and PIs have
    * the top word the same as their owner and the bottom half reflecting their relative position.
    */

    protected long getSequenceNumber() {
        return parent.getSequenceNumber() + index;
    }
        
}

//
// The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
// you may not use this file except in compliance with the License. You may obtain a copy of the
// License at http://www.mozilla.org/MPL/ 
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations under the License. 
//
// The Original Code is: all this file. 
//
// The Initial Developer of the Original Code is
// Michael Kay of International Computers Limited (mhkay@iclway.co.uk).
//
// Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved. 
//
// Contributor(s): none. 
//